Snowy, I once thought as you do, and that's why I almost ended up killing myself. There IS no limit. You will diet and diet until... quite aptly, you no longer die-t, you merely die.
I keep saying it on this thread, but the only way to be a great anorexic, to truly excel at it, is to kill yourself by it. Because once again, I'm repeating myself, but the strongest phrase I always use is - you'll be as skinny as you'll ever be when you're lying six feet under - then you won't HAVE any pesky matter on your bones!
I suggest you look through the past two pages, we talk a lot about the self-depreciative nature of the disorder and how a lot of the time, it's because you feel you have no other innate "talent" or "strength". You're not REALLY good at starving yourself, you've set up a set of arbitrary, pointless rules that mean nothing in the real world. The elation you're feeling is all fake; fabricated by your mind.
Alternatively you COULD get skinny as all hell as I did, but unlike me at that stage of mere weeks to live, with Kidney and Liver failure, yellow skin, arguing with them that I'm "still not light enough", decide that life IS the lesser option, and just call it a day? I'm sure even the most devout, deluded person would question that. X